Callihg device



J. A. KROPP.

CALLING DEVICE.

APPLICATION FILED DEC. 1a. 1916.

1 ,324g356. Patented Dec. 9, 1919.

ln yen for barren srarns earner JOHN BuKROPP, OF OAK PARK, ILLINOIS, ASSIGNOR TO WESTERN ELECTRIC COMPANY, IIECORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

cALLIne nnvrcn.

Specification of Letters Patent.

Patented lDaecu s, 191.9.

Application filed December 13. 1916. Serial No. 136,634.

To all whom it may concern:

' Be it known that I, JOHN A. KROPP, a citizen of the'United States, residing at Oak Park, in the county of Cook and State. of Illinois, have invented certain new and useful Improvements in Calling Devices, of which the following is a full, clear, concise, and exact description.

This invention relates to calling devices, and more particularly to impulse senders for automatic or semi-automatic telephone systems in which the switches used for the building up of a connection are directively controlled by current impulses sent from a subscribers station or an operators position.

The object of this invention is to provide a new and improved calling device which is suitable for mounting on a telephone transmitter. I

A feature of the invention is the mounting of a finger dial in such a way as to be rigidly held, yet easily rotatable, without the use of a spindle or shaft such as has been previo sly used.

nother feature of the invention is. the

substitution of lugs punched out from a disk for a notched wheel. By the use of such lugs projecting from the governor controlling wheel, the provision of a separate notched orv gear wheel for actuating the impulse sprlngs is made unnecessary.

Still another feature of the invention is the simplicity and ease with which the sender may be attached to or the transmitter.

Other new and useful features of this invention will appear from the following detailed description and the appended claims.

The invention is illustrated in the accom panying drawings, in which'Figure 1 1s a frontelevation of the calling device and a transmitter; Fig. 2 is a sectional view of the same taken on line 22 of Fig. 1; Fig. 3 is a rear elevation of the device showingthe mechanical structure of same- Fig. 4 1s a view, showing details of assembly; and Fig.

5 is a detail View of 'a shunt spring and an operating roller therefor.

The various partsof the calling device are inclosed in a case 1 which is provided with a groove 28 to fit over the upper edge of the face plate of an ordinary telephone transmitte An opening in the front of the case 1 alremoved from lows the passage of the transmitter mouthplece 33 and of the drum 13. A ring 4-, carrying characters such as numerals 1 to 0 spaced around its periphery, is placed on the front of the case 1. A transparent cover 5 and an escutcheon 6 to protect the cover are placed over the character carrying ring 4:, the three parts 4, 5 and 6 being secured to the case by the lip of a ring 2. The ring 2 is itself astened by a nut 7. The inner edges of the ring 2 are beveled to keep in position the ball bearings 11. I

A finger dial 10 is made in the form of a flange on a drum 13', which is substantially conical in shape so as to fit over the mouthpiece 33 of the telephone transmitter. Finger holds'30 corresponding to the characters on the ring 4 are provided in the flange of the drum for actuating the dial; A portion of the outside of the drum 13 is threaded to receive rings 9. The rings 9 in cooperation with the ring 2 form a ball race in which run balls 11, thus mounting the finger dial 10 very securely yet allowing easy rotation. Although the drum 13 is shown herein mounted on ball bearings, it is to be under stood that roller or any suitable type of bearings might be employed.

A' governor wheel 8 is also threaded on the drum 13. The governor Wheel 8 is toothed and is provided near its periphery with lugs 12 which are punched out so as to project from the front of the wheel itself, a lug being provided to correspond to each character on the ring 4. Carried on the back of the governor wheel is a roller 29 hold open shunt springs 17 and 18, by engaging "a lug on the spring 17 as illustrated in Fig. 5. \Vhen, however, the finger dial is in any position other than normal, the removal of the roller 29 from engagement with the lug allows the closure of these springs. Supported between a 'bracket 22 and the case 1 is a two-armed pawl 14, the arm 15 being adapted to engage the lugs 12 during rotation of the finger dial, the arm 16 carrying a roller 21 to actuate the impulse springs 19 and 20. The pawl 14: is held in normal position by a retractile spring (not shown).

A motor spring 23 encircles the inner portion of the drum 13 and has one end attached to the drum so. as to oppose rotation of the drum in a clockwise direction as viewed from the front.

Any desirable form of governing device may be used with this calling device, that disclosed 'in the patent to Forsberg, 1,161,-'

854, being suitable for this purpose. The governor case 32 is made fast to the case 1 in any convenient manner. The governor is actuated by the teeth of the wheel 8 meshing with a pinion 27 which operates the train of wheels indicated in Fig. 3.

A clamp 21 is provided to cooperate with the groove 28 in holding the calling device on the face plate. The clamp 21 may be attached to the case 1' by a screw 25. The calling device may be securely attached to any standard telephone instrument by the simple Process of unscrewing the mouthpiece, fitting groove 28 over the face plate 3 of the transmitter, adjusting clamp 24 and tightening the screw 25. This does not necessitate a special design of instrument for use with this device.

When in place the sender does not expose any parts to be tampered with or to be broken off, neither can it be accidentally knocked out of position. On the other hand it is easily removable for any necessary adjustment or replacing of parts.

Other details of construction will be understood from the following description of the operation of the device.

If the user desires to send out, for instance, a signal corresponding to the number 7, he engages the finger hold 30 which is normally over the number 7 and rotates the dial in a clockwise direction until the stationary stop 31 is reached. In response to the actuation of the dial 10 motor spring is wound up and the governor 32 is rotated.

The lugs 12 engage the arm 15 of pawl 14,

but, as will be seen from Fig. 3, no movement is transmitted to the contact spring 19, since the motion of the roller 21 is away from said spring during the rotation of the dial in a counter-clockwise direction as viewed from the rear. The rotation of the governor wheel carries the roller 29 away from the contact spring 17 which thereupon engages the spring 18. The springs 17 and 18 will stay closed until the return of the finger dial to normal and may be used to shunt out the receiver of the telephone set.

On reaching the stop 31, the user removes his finger from the finger hold, and the dial 10 is returned to normal by means of the motor spring 23, its rate of rotation being controlled by the governor During the return of the dial to normal the governor Wheel 8 Will be rotated in a clockwise direction, as'shown in Fig. 3, and each lug 12 in engaging the arm 15 will actuate roller 21 so as to open the contact between springs 19 and 20, thus sending one impulse. As the lugs 12 correspond with the characters on the ring 4 and with the finger holds 30,

the desired number of impulses will thus be sent, and the dial on reaching its normal position will be ready for sending the next signal.

What is claimed 15: 1. The combination with a telephone transmitter including a mouthpiece of a calling device encircling the mouthpiece of said transmitter.

2. In a calling device, a hollow drum, a finger dial fixed thereto, a member surrounding said, drum, and means for rotatably mounting said drum in the inner side of said surrounding means.

8. In calling device, the combination with a finger dial, a hollow drum carrying said finger dial and a case surrounding said drum of bearings between the inner side of said case and said drum for rotatably mounting said drum in said case.

4:. In a calling device, a finger dial a drum for supporting said finger dial, rings on said drum, a case, a ring secured to said *ase, and bearing members, said case carried ring and said drum carried rings cooperating to form a race for said bearing members.

5. The combination with a telephone transmitter, including a face plate and a mouthpiece, of a calling device attached to said face plate and surrounding said mouthpiece.

6. The combination with a telephone transmitter, including a mouthpiece, of a calling device having an opening therethrough arranged to receive said mouthpiece. I

T. The combination with a telephone transmitter, including aface plate and a mouthpiece, of a calling device to encircle said mouthpiece and to be attached to said .face plate.

8. A telephone transmitter, a face plate on said transmitter, a calling device, a clamp and a screw, said clamp and said screw acting to hold said calling device on said face plate.

9. The combination with a telephone transmitter including a face plate and a mouth piece, of a calling device detachably secured to said face plate and surrounding said mouth piece.

10. The combination with a telephone transmitter including a face plate and a mouth piece, of a calling device, said device comprising a supporting member secured to said face plate and surrounding said mouth piece. and a finger dial rotatably mounted on said supporting member.

11. The combination with a telephone transmitter including a face plate and a mouth piece, of a calling device, said device comprising a supporting member detachablv secured to said face plate and surrounding said mouth piece, and a finger dial rotatably mounted on said supporting member.

12. The combination with a telephone transmitter includinga face plate and a mouth piece, of a calling device, said device comprising adrum secured to said face plate and arranged to receive said mouth piece.

13. The combination with a telephone transmitter including a face plate and a mouth piece, of a calling devlce, said device comprising a drum detachably secured to said face plate and arranged to receive said mouth piece.

In witness whereof I hereunto subscribe my name this 8th day of Dec, A; D., 1916.

JOHN A. KROPP. 

